Cell Cycle Control of Ovarian Granulosa Cells in Tumors and Cysts

Abstract

Ovarian granulosa cell tumors (GCTs) behave unpredictably. Stage I patients suffer recurrences many years after treatment, and histopathologic evaluation of the primary GCT offers few clues. p21IPl/wafl (Waft), the principle downstream effector of the p53-dependent pathway of growth control, inhibits cyclin-dependent kinases responsible for conversion of GI to S in the cell cycle. This study hypothesizes that immunohistochemistry for these proliferation-related markers will help discern granulosa cell growth control and may predict the GCTs' clinical behavior. Paraffin sections from a surgical series of 43 GCTs (34 primary and 9 recurrent: 19 diffuse and 18 typical adult; 6 juvenile type) and 12 benign cysts (8 follicular and 4 corpora luteal) were immunostained for Waft and p53. Ki67 (MIB-1 clone) proliferation index is the percent of nuclei immunoreactive on a count of at least 400. The 43 GCTs stained as follows: 40% Waft + (11 St = < 10%, 4 S2 = 10-50%, and 2 S3 = > 50% of nuclei) and 28% p53 + (2 W = weak, 8 S 1, 2 S2). All p53 + GCTs stained with Waf 1; the number of immunoreactive nuclei correlated (P < .00001). Juvenile more often than adult type GCTs exhibited Waf 1 (6/6) and p53 staining (5/6) (P < .001). No difference in pS3 or Waft staining was present in primary compared with recurrent GCTs. Ki67 proliferation index for GCTs ranged from 1 to 50% (mean, 13.8%; median, 10.9%) and associated with both p53 and Waft (P < .000 1). The 12 benign cysts stained as follows: 100% Waft + (6 S1, 5 S2, 1 S3) and 75% p53+ (4 W, 4 S1, 1 S2). Of the 43 patients, 41 were available for follow-up study: 15 suffered recurrences after 16-133 (mean 59.3, median 55) months, and 26 were disease-free 21-369 (mean 78.2, median 57.5) months after diagnosis. Waft staining of the primary GCT does not help predict recurrence. All GCTs immunoreactive for p53 produce Waft, suggesting detection of an active wild type p53 rather than overproduction of mutant p53. Waft is produced by granulosa cells in all benign functional cysts, suggesting a physiologic role in the ovulation sequence. Waf t's association with proliferation in GCTs suggests possible physiologic feedback. Proliferation (correlated with histopathologic grading) in GCTs may signify appropriate feedback control; thus it is not a predictor of aggressive clinical behavior.